Drying apparatus



Sept. 5, 1933. A s 1,925,900

DRYING APPARATUS Filed Dams 1 1931 A Hermann Housby H' l' M EZ Patented Sept. 5, 1933 DRYING APPARATUS Hermann Haas, Lennep, Germany Application December 4, 1931, Serial No. 578,863, and in Germany December 19, 1930 2 Claims.

This invention relates to drying apparatus which is designed for drying articles of a ceramic nature, such for instance as articles made of clay, porcelain, gypsum, etc. 5 In the drying of ceramic articles it is a desideratum that the molded articles should first receive a preliminary heating in moist heated air because if the preliminary heating of the cold molded articles is accomplished by subjecting the articles to dry hot air the surfaces of the articles are apt to crack.

It is also a desideratum that the final drying of the articles should be in hot dry air because if hot moisture-laden air is used for the final drying operation the interstices in the articles would be too much enriched by moist fumes.

The present invention has for its object to provide an improved drying apparatus which meets these requirements in that it is so arranged that when the articles to be dried are first introduced in the drying chamber they will be subjected to the action of moist heated air to thoroughly heat the articles and partially dry them and when the articles are thoroughly heated and partially dried they will then be subjected to the action of dry heated air which will complete the drying operation.

I A drying apparatus capable of operating in this way and which embodies my invention comprises a drying chamber which is divided into two compartments, one of which compartments contains moisture-laden heated air and in which the articles receive a'preliminary heating, (said compartment, for convenience, being referred to as a 3 primary compartment), and the other of which compartments contains relatively dry heated air and in which the articles receive their final drying, (which will, for convenience, be referred to as a secondary compartment).

Situated between the compartmentsv is a heating chamber and means are provided for causing the moisture-laden air in the primary compartment to circulate through said compartment and the heating compartment, and also to cause the dry heated air in the secondary compartment to circulate therethrough and through the heating compartment and further to cause a continual withdrawal of the moist air from both compartments.

'It will be understood that the device also includes a suitable endless conveyer to convey the articles through the compartments successively.

In order to give an understanding of the invention I have illustrated in the drawing somewhat diagrammatically an apparatus embodying the invention which will now be described.

Fig. 1 is a schematic view illustrating an apparatus embodying my invention;

Fig. 2 illustrates the construction of the airforcing apparatus used for causing circulation through the compartment containing the moist air or the air with relatively high humidity;

Fig. 3 illustrates the type of air-forcing device which would be used for causing circulation of air through the secondary compartment which contains the dry heated air;

Fig. 4 illustrates the character of air-forcing mechanism which would be used for withdrawing air from both compartments;

Fig. 5 illustrates the mounting of the air-forcing element by which the circulation of the air is secured.

In Fig. 1 the drying chamber is indicated generally at A, it having an entrance opening E at one side into which the articles to be dried are introduced and another opening J at the opposite side through which the dried articles are removed.

The articles to be dried are carried through the 30 drying chamber by means of an endless conveyer comprising endless chains K from which are suspended cradles or slings S on which the articles are placed. This endless chain conveyer passes around a series of pulleys R R R", R R situated within the chamber A and the pulleys R R situated outside. The walls of the chamber A are provided with openings F and G through which the conveyer passes.

Situated within the chamber A between the pulleys R and R is a heating compartment H in which are located steam pipes I for furnishing the-desired heat. The heating compartment divides the main heating chamber into two compartments O and P. The compartment 0 which will be referred to as a primary compartment, contains moisture-laden air while the compartment P, which will be referred to as a secondary compartment contains relatively dry heated air. The heating compartment H communicates with the primary compartment 0 through an opening N and with the secondary compartment P through another opening T.

The arrows indicate the direction of movement of the endless chain and it will be observed that the. chain passes downwardly adjacent the entrance opening E, then passes around the pulleys R, and R which are in the primary compartment 0 and thence around the pulley R situated below the heating compartment and thence around the pulleys R and R which are in the secondary compartment and thence out through the opening F and around the pulleys "R and R and back into the primary compartment through the open- .ing G. During the travel from the pulley R to pulley R. the cradles or slings pass adjacent the openingJ to permit the articles to be removed.

A series of air-forcing elements are employed to cause a circulation of the heated moisture-laden air through the primary compartment 0 and the heating compartment H as shown by the arrows B in Fig. 1 and also to cause another circulation of relatively dry heated air through the secondary compartment P and the heating compartment H as shown by the arrows C in Fig. 1, and further to withdraw moist air from both compartments.

The air which is circulated through the primary compartment 0 and the heating compartment H will be relatively moist because this air will cause evaporation of water from the molded articles as they are introduced into the drying chamber and hence the preliminary heating of the cool articles is accomplished through a moist heating medium which serves to partially dry the articles without causing them to crack or check.

If desired, an atomizing nozzle Z may be provided in the preliminary compartment 0 for delivering additional moisture to the air in order to secure the requisite degree of saturation or humidification of the air.

The air which circulates through the compartment P and the drying compartment H is relatively dry, partly because the articles to be dried have already discharged the part of their moisture before they reach the compartment P and partly because no additional or supplementary moistening of the air is provided as in the case of the compartment 0. Hence the humidity of the air in the compartment P will be very much less than in the compartment 0.

The chamber A is provided with an exhaust opening M from which moist air from both compartments may be discharged.

The air-forcing mechanism designed to operate as above described is illustrated in Figs. 2 to 5. This consists of a series of blowers L L L L L each blower being of the centrifugal type and having an axial inlet and a tangential discharge, and the rotor elements of all the blowers being mounted on a common shaft D. These blowers are situated above the heating compartment H and the blower L is arranged to cause the circulation of the air through the preliminary compartment 0. For this purpose the discharge A of said blower L is directed downwardly into the heating compartment H while the suction inlet of said blower has communication with the upper end of the primary compartment 0. The operation of the blower L, therefore, will be to cause circulation of air downwardly through the heating compartment H and through the opening N into the compartment 0 and then upwardly through the compartment 0 back to the inlet of the blower L' as indicated by the arrows B with the heating compartment H and the operation of these blowers is to draw air from the heating compartment and force it into the upper end of the compartment P, the air circulating The blowers which cause a circulation of airthrough the opening T as shown by the arrows C in Fig. 1.

The blowers L L are arranged to withdraw moist air continuously from both compartments. These blowers have their discharge W directed upwardly as shown in Fig. 4 and the inlet of the blowers is connected to the upper ends of the compartments 0 and P so that as the blowers operate moist air will be drawn from the compartments O and P and delivered upwardly through the flue or discharge opening M to the exterior of the casing A as shown by the arrows V in Figs. 1 and 4. It will be understood that, if necessary, the heating compartment H may have any desirable vertically-extending deflectors or battles to ensure the circulation of the air in the manner above described and illustrated in Fig. 1.

It will be understood that suitable provision may be made for regulating the volume of air circulated by the difierent blowers so as to adapt the circulation to the existing requirements and so as to maintain the desired relative degrees of humidity in the compartments 0 and P.

It will further be understood that the size of the apparatus and the relative location of the parts may be varied without departing from the spirit of the invention.

The blower assembly consisting of the plurality of blowers on the common shaft may be made as a separate unit which may be readily installed in the plant as it is erected in any desired position between'the chain loops and with this arrangement it is possible to standardize the difierent parts of the drying apparatus so that the erecting of a drying plant involves merely ordering the requisite number of standardized parts.

The principal feature of the invention, however, resides in the arrangement by which the series of blowers mounted on a common shaft operate to cause a circulation of moisture-laden air through the primary compartment 0 and the heating compartment H, a separate circulation of dry heated air through the compartment P and the compartment H and also a continual withdrawal of moist air from both compartments.

. I claim:

1. A drying apparatus for drying ceramic articles comprising a chamber divided by a single heating compartment into a primary drying compartment and a secondary drying compartment, said heating compartment communicating with both the primary and secondary drying compartments, a conveyer for conveying the articles to be dried first through the primary compartment and then around the heating compartment, and then through the secondary compartment, anda plurality of blowers mounted on a common shaft, certain of said blowers being arranged to cause a circulation of moisture-laden air through the primary compartment and the heating compartment and other of said blowers being arranged to cause a circulationof air through the secondary compartment and the heating compartment while the other blowers are arranged to provide a continual withdrawal of moist air from both compartments.

2. A drying apparatus for drying ceramic articles comprising a chamber divided by a single vertically-extending heating compartment into a primary drying compartment on one side of the heating compartment and a secondary drying compartment on the other side of the heating compartment, said heating compartment extend ing from the top of the chamber nearly to the bottom thereof and communicating with both the primary drying compartment and secondary drying compartment, a conveyer for conveying the articles to be dried first through the primary drying compartment and then downwardly around the lower end of the heating compartment and then through the secondary drying compartment, means to deliver moisture to the primary drying compartment to maintain a desired degree 

